Two main types of vacuum cleaner are known at present. The first type of vacuum cleaner, which is the most widespread, includes a flexible bag which is permeable to air and which is disposed in an airtight enclosure between a suction orifice and a suction device. Air sucked by the suction device flows through the wall of the flexible bag which then acts as a filter and retains the dirt contained in the sucked-in air. Such a vacuum cleaner is not suitable for sucking up a liquid since the liquid would flow through the pores of the flexible bag, nor can it be used with damp substances which would very quickly clog the pores of the flexible bag. Further, flexible bags are either made of cloth, in which case it is necessary to empty them out in order to reuse them and this is a particularly disagreeable operation to perform, or else they are made of paper, in which case they are fragile and may tear while being handled which makes it necessary to clean out the vacuum cleaner itself and to vacuum back up the dirt which has fallen onto the ground.
In the second type of vacuum cleaner, a rigid receptacle is disposed in an airtight enclosure with an opening facing the suction orifice, and the suction device is disposed on a side opposite to said opening. The air sucked by the suction device flows around the rigid receptacle while the dirt is projected, generally under gravity, into the rigid receptacle. Although such a vacuum cleaner is capable of picking up wet dirt and even liquids, it is still necessary to transfer the contents of the rigid receptacle into a garbage bin. Such a device is therefore unsuitable for vacuuming harmful particles or substances that redisperse in the atmosphere during handling, such as asbestos for example. Attempts have indeed been made to dispose an airtight flexible bag in the rigid receptacle, but it has been observed that the bag is then sucked into the suction device when the device is switched on, and as a result it is not possible to use an airtight flexible bag in existing vacuum cleaners.
An object of the present invention is to provide a vacuum cleaner in which the dirt is directly collected in an airtight flexible bag.